Question

9. The perimeter of a rectangle is 104 cm. If its width is 2 cm more than one third of its length, find the
length and breadth of the rectangle.
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Answer 1

Answer:

This is a classic example of finding mean and standard deviation using Z values.

From this page find the Z value corresponding to 31% area under the curve and 92% (100-8) percent area under the curve.

Math Is Fun Virtual Manipulative

Note: You'll probably be given tables to lookup in your quizzes.. they're a bit confusing. But you might as well learn how to use it.

As you know:

Z=X−μσZ=X−μσ

Put in X and Z values values twice, you'll have two linear equations. Solve them and the answer is yours!